I cancelled a SIM card contract with Telkom in March and then cancelled it after they failed to deliver both the sim card and the router. I have called them unsuccessfully to sort out this matter and every time I call them they tell me about the matter be

I cancelled a SIM card contract with Telkom in March and then cancelled it after they failed to deliver both the sim card and the router. I have called them unsuccessfully to sort out this matter and every time I call them they tell me about the matter being escalated to the relevant person, they will be debuting me for the 3rd month on the 15 July as I saw this on my July statement, they still haven't rectified my monthly premium. I don't what I should do to have this matter resolved as it is messing up with debits.